S. Doering, M. Seitz, P. Rodger, W. Werner, Qimonda Dresden GmbH & Co. OHG, Dresden, Germany

Summary: It was shown that using AFM based probing equipment additional information regarding the location of the node leakage could be obtained. Since the deep trench is a vertical device, the gained z-information is of value. In this example study three analysis steps were done. At first the node leakage was verified at contact level. In a second step the sample was deprocessed into the pWell level and a current image was obtained, confirming the node leakage to be located below this level. In the third step the sample was further deprocessed to the edge of the nWell level. Again a current image was obtained, this time showing no leakage any more. With those three measurements we confined the node leakage to the small (compared to the whole deep trench) nWell region.